When a packet service and a time division multiplexing (Time Division Multiplexing, TDM) service are transmitted in an optical transport network (Optical Transport Network, OTN), if different OTN devices are adopted to transmit the packet service and the TDM service, the packet service and the TDM service need to be switched by using different devices, causing a complex device form and a waste of device resources.
In order to transmit a packet service and a TDM service on one device, a circuit emulation service (Circuit Emulation Service, CES) technology is provided in the prior art, which can encapsulate a TDM service into a packet, and transmit the packet into which the TDM service is encapsulated, together with a packet into which a packet service is encapsulated. However, because transmission paths used are the same when the TDM service and the packet service are transmitted together, when the packet service and the TDM service are switched to another device by using a same device during a transmission process, uncertainty of a switching time required by the packet service is relatively high due to uncertainty of a transmission delay in the packet service; due to a characteristic that the TDM service must be continuously transmitted, the TDM service also needs a large buffer to absorb uncertainty of a switching time, thereby increasing a transmission delay of the TDM service.